Abstract: An apparatus for transferring wafers by a robot blade and a method for using the apparatus are disclosed. In the apparatus, a robot blade that is equipped with distance sensors mounted in a bottom surface of the blade is provided which senses the distance between the bottom surface of the robot blade and an adjacent surface below the robot blade such that any possible scratching of the adjacent surface is eliminated. The adjacent surface below the robot blade may be a wafer surface in a wafer cassette, or a wafer pedestal surface in a process machine. The distance sensors are mounted in recesses in the bottom surface of the blade which may be suitably capacitance sensors, ultrasonic sensors or optical sensors. The distance sensed by the distance sensors is analyzed by a controller and compared to a predetermined value of a minimum allowable distance such that any danger of scratching the adjacent surface is eliminated.